Relaxation oscillator

摘要

A relaxation oscillator shares charging current and comparator biasing current between just two current sources, thereby relaxing requirements on total supply current. The resulting reduction in power consumption has no adverse effect on the speed and accuracy of the oscillator. A switching arrangement directs charging and biasing currents between the two current sources and two charging capacitors and their associated comparators.

主权项

1. An oscillator circuit, comprising:
a flip-flop for generating a clock signal at an output thereof; first and second current sources; first and second capacitors; first and second comparators for comparing a voltage across the first and second capacitors respectively with a reference voltage, wherein each comparator has an output connected to an input of the flip-flop; and a switching circuit connected to the output of the flip-flop and arranged to direct (i) on a first half cycle of the clock signal, a first charging current to the first capacitor from the first current source and to direct a first biasing current to the first comparator from the second current source, and (ii) on a second half cycle of the clock signal, a second charging current to the second capacitor from the second current source and to direct a second biasing current to the second comparator from the first current source.